CN102934469B - Wireless communication method, wireless communication apparatus and wireless communication system - Google Patents

Abstract

This invention is directed to suppressing the overhead of wireless communications, thereby allowing data transmissions to be efficiently performed. A wireless communication apparatus (1) includes a control unit (1a) and a transmission unit (1b). When no connection with a wireless communication apparatus (2) has been established, the control unit (1a) determines a timing at which control information to be used in a process to establish the connection can be transmitted to the wireless communication apparatus (2). The transmission unit (1b) transmits a message, which includes data different from the control information, to the wireless communication apparatus (2) at the determined timing. The wireless communication apparatus (2) includes a reception unit (2a) and a data processing unit (2b). The reception unit (2a) receives, from the wireless communication apparatus (1), the message that was transmitted at the timing at which the wireless communication apparatus (1) could transmit the control information. The data processing unit (2b) extracts the data included in the received message.

Description

Wireless communication method, wireless communication device, and wireless communication system

technical field

The present invention relates to a wireless communication method, a wireless communication device and a wireless communication system.

Background technique

Currently, wireless communication systems such as mobile phone systems are widely used. In addition, in order to further increase the speed and broadband of wireless communication, research on next-generation wireless communication technology is continuously and actively conducted. For example, in the 3GPP (3rd Generation Partnership Project: 3rd Generation Partnership Project), which is one of the standardization groups, a wireless communication system called LTE (Long Term Evolution, Long Term Evolution) and a wireless communication system developed from LTE are proposed. A wireless communication system called LTE-A (Long Term Evolution-Advanced, Advanced LTE) (see, for example, Non-Patent Documents 1 and 2).

Such a wireless communication technology can be used not only for wireless communication by a terminal device operated by a user such as a mobile phone, but also for wireless communication by various other devices such as measuring equipment. For example, consider realizing a system in which metering devices such as gas meters and electricity meters report metering data to a server via a wireless communication network. In 3GPP, MTC (Machine Type Communication) is proposed as a wireless communication method without interaction with users (for example, see Non-Patent Document 3).

prior art literature

non-patent literature

Non-Patent Document 1: 3rd Generation Partnership Project, "Requirements for EvolvedUTRA(E-UTRA) and Evolved UTRAN(E-UTRAN)", 3GPP TR 25.913V7.3.0, 2006-03.

Non-Patent Document 2: 3rd Generation Partnership Project, "Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA)", 3GPP TR36.913 V8.0.1, 2009-03.

Non-Patent Document 3: 3rd Generation Partnership Project, "Service requirements formachine-type communications", 3GPP TS 22.368 V1.0.0, 2009-08.

Contents of the invention

The problem to be solved by the invention

However, the wireless communication device can enter a state in which the connection related to wireless communication is canceled (idle state) when not transmitting and receiving data. The wireless communication device in the idle state can establish a connection again by performing a predetermined procedure (message transmission and reception) with the wireless communication device of the communication partner.

However, there is a problem that, when the wireless communication device intermittently transmits data, when the connection is established and released every time the data is transmitted, the system overhead caused by the steps of establishing and releasing the connection becomes large, and the data transmission time is increased. Efficiency drops. In particular, in a wireless communication system in which the amount of data to be transmitted at one time is expected to be relatively small, such as the MTC system, the above-mentioned system overhead has a greater influence on data transmission efficiency.

The present invention has been made in view of these points, and an object of the present invention is to provide a wireless communication method, a wireless communication device, and a wireless communication system capable of efficiently transmitting data while suppressing system overhead of wireless communication.

means to solve the problem

In order to solve the above problems, there is provided a wireless communication method in a wireless communication system including a first wireless communication device and a second wireless communication device. The first wireless communication device transmits data to the second wireless communication device. With this wireless communication method, when the first wireless communication device has not established a connection with the second wireless communication device, it transmits a message including data different from the control information to the second wireless communication device at a timing when the control information can be transmitted. , where the control information is used for connection establishment processing. The second wireless communication device receives, from the first wireless communication device, a message transmitted at a timing at which the first wireless communication device can transmit the control information. The second wireless communication device extracts data included in the received message.

Furthermore, in order to solve the above-mentioned problems, a wireless communication system including a first wireless communication device and a second wireless communication device, wherein the first wireless communication device transmits data to the second wireless communication device is provided. The first wireless communication device has a control unit for determining a timing at which control information can be transmitted to the second wireless communication device when the connection with the second wireless communication device is not established, wherein the control information is used for connection establishment processing. and a transmitting unit that transmits a message including data different from the control information to the second wireless communication device at a timing determined by the control unit. The second wireless communication device includes: a receiving unit that receives from the first wireless communication device a message transmitted at a timing when the first wireless communication device can transmit control information; and a data processing unit that extracts the information contained in the message received by the receiving unit. The data.

Invention effect

According to the wireless communication method, wireless communication device, and wireless communication system described above, it is possible to efficiently transmit data while suppressing system overhead of wireless communication.

The above and other objects, features and advantages of the present invention will become more apparent by the accompanying drawings showing preferred embodiments as examples of the present invention and the related following description.

Description of drawings

FIG. 1 is a diagram showing a radio communication system according to a first embodiment.

FIG. 2 is a diagram showing a wireless communication system according to a second embodiment.

FIG. 3 is a block diagram illustrating an MTC device.

FIG. 4 is a block diagram illustrating a base station.

FIG. 5 is a sequence diagram showing the flow of terminal registration.

FIG. 6 is a diagram showing the data structure of Msg3.

FIG. 7 is a flowchart showing data transmission processing.

FIG. 8 is a flowchart showing data reception processing.

FIG. 9 is a sequence diagram showing the flow of data transmission without establishing an RRC connection.

FIG. 10 is a sequence diagram showing the flow of data transmission for establishing an RRC connection.

Detailed ways

Hereinafter, this embodiment will be described in detail with reference to the drawings.

[First Embodiment]

FIG. 1 is a diagram showing a radio communication system according to a first embodiment. The wireless communication system according to the first embodiment includes wireless communication devices 1 and 2 . For example, it is considered that the wireless communication device 2 is installed as a base station, and the wireless communication device 1 is installed as a participant station for accessing the wireless communication device 2 . The wireless communication device 1 transmits data to the wireless communication device 2 through wireless communication. The wireless communication devices 1 and 2 can appropriately establish and release a wireless communication connection.

The radio communication device 1 includes a control unit 1a and a transmission unit 1b. When the connection between the wireless communication devices 1 and 2 is not established, the control unit 1a determines the timing at which control information can be transmitted to the wireless communication device 2, wherein the control information is used for connection establishment processing. The transmission unit 1b transmits a message including data different from the control information to the wireless communication device 2 at the timing determined by the control unit 1a.

The wireless communication device 2 includes a receiving unit 2a and a data processing unit 2b. The receiving unit 2a receives a message transmitted at a timing when the wireless communication device 1 can transmit control information used for connection establishment processing from the wireless communication device 1 that has not established a connection with its own device. The data processing unit 2b extracts data different from the control information from the message received by the receiving unit 2a. The data processing unit 2b transmits the extracted data to a predetermined communication device, for example.

Here, the connection established between the wireless communication devices 1 and 2 may be a connection defined by a radio resource control (RRC: Radio Resource Control) protocol which is a layer 3 protocol. The above control information may be RRC control information. The timing at which the wireless communication device 1 can transmit control information includes, for example, the timing before the connection is established after the wireless communication device 1 performs random access to the wireless communication device 2 .

In addition, the above-mentioned message transmitted by the wireless communication device 1 may include both control information and data different from the control information, and may selectively include either one of the control information and data different from the control information. When the wireless communication device 2 extracts data different from the control information from the received message, the wireless communication with the wireless communication device 1 can be terminated without performing a connection establishment process.

In addition, identification information of wireless communication devices that may be able to transmit data different from the control information at the above timing may be registered in wireless communication device 2 in advance, and wireless communication device 1 may insert the identification information of its own device into the message. At this time, it is considered that the radio communication device 2 extracts data different from the control information from the message only when the identification information included in the received message is pre-registered. In addition, the wireless communication device 1 may insert flag information indicating whether or not data different from the control information is included into the message. At this time, the wireless communication device 2 can determine whether to perform processing for extracting data different from the control information from the received message based on the flag information.

With the wireless communication system of the first embodiment, when the wireless communication device 1 has not established a connection with the wireless communication device 2, it transmits a message including data different from the control information to the wireless communication device at the timing when the control information can be transmitted. In the communication device 2, the control information is used for connection establishment processing. The wireless communication device 2 receives from the wireless communication device 1 a message transmitted at a timing when the wireless communication device 1 can transmit control information. And, the wireless communication device 2 extracts data included in the received message.

Therefore, data can be transmitted from the wireless communication device 1 to the wireless communication device 2 before the connection between the wireless communication devices 1 and 2 is established. In addition, the wireless communication device 2 may end the wireless communication with the wireless communication device 1 without performing the process of establishing a connection after receiving the data. Thus, it is possible to efficiently transmit data while suppressing the overhead of wireless communication. The wireless communication method described above is particularly effective when the wireless communication device 1 transmits data intermittently and when the amount of data to be transmitted at one time is small.

In addition, the wireless communication system according to the first embodiment can be realized using LTE and LTE-A wireless communication technologies. In addition, it can also be implemented as an MTC system. In the second embodiment described below, an example of an MTC system realized by using LTE or LTE-A wireless communication technology will be given.

[Second Embodiment]

FIG. 2 is a diagram showing a wireless communication system according to a second embodiment. The wireless communication system of the second embodiment includes MTC devices 10 , 10 a , a base station 20 , an MTC server 30 , and a network 40 . The base station 20 is capable of data communication with the MTC server 30 via the network 40 .

The MTC devices 10 and 10a are wireless communication devices connected to meters installed in homes and offices. As the measuring meter, a gas meter, an electric meter, a water meter, etc. are considered. The MTC devices 10, 10a access the base station 20, and transmit various data including MTC data representing the measured value of the meter to the MTC server 30 via the base station 20. It is expected that the amount of MTC data sent by the MTC device 10, 10a at one time is small. In addition, it is expected that the cycle of sending MTC data is a cycle as long as a one-month cycle.

In addition, the MTC device 10 has a function of transmitting MTC data without establishing an RRC connection with the base station 20 as described later. On the other hand, the MTC device 10a does not have a function of transmitting MTC data without establishing an RRC connection. Here, the RRC protocol is a layer 3 protocol related to wireless communication, and includes a function of mobility management.

The base station 20 is a communication device that performs wireless communication with the MTC devices 10 and 10 a and performs wired communication with the MTC server 30 . The base station 20 accepts access from the MTC devices 10 and 10a, and receives data from the MTC devices 10 and 10a wirelessly. Upon receiving the MTC data by wireless, the base station 20 transmits the MTC data to the MTC server 30 via the network 40 . In addition, the network 40 includes, for example, a core network managed by a communication carrier and the Internet.

The MTC server 30 is a server computer that collects MTC data from the MTC devices 10, 10a and monitors meters. The collected MTC data is used eg for billing management. The MTC server 30 can be installed within the network of a company (for example, a gas company, an electric power company, a water company, etc.) that installed a meter.

FIG. 3 is a block diagram illustrating an MTC device. The MTC device 10 has a reception unit 11 , a meter management unit 12 , a transmission data generation unit 13 , a transmission unit 14 , and a control unit 15 .

The receiving unit 11 performs radio signal processing on a signal received from the base station 20 via an antenna, and down-converts a high-frequency radio signal into a low-frequency baseband signal. Furthermore, the receiving unit 11 performs demodulation and error correction decoding on the baseband signal, and extracts user data and control information transmitted from the base station 20 . The receiving unit 11 outputs the extracted user data to the meter management unit 12 , and outputs the extracted control information to the control unit 15 . The user data includes, for example, an instruction for managing/operating the meter sent by the MTC server 30 . The control information includes random access response and RRC control information which will be described later.

The meter management unit 12 manages meters based on the user data acquired from the reception unit 11 . The meter management unit 12 monitors the measured value of the meter, and outputs MTC data indicating the measured value to the transmission data generation unit 13 at a predetermined cycle or at a timing specified from the MTC server 30 . The measured value of the meter can include the consumption of "items" such as gas, electricity, and water.

The transmission data generation unit 13 generates a message to be transmitted to the base station 20 under the control of the control unit 15 and outputs it to the transmission unit 14 . The transmission data generating unit 13 sometimes inserts the MTC data acquired from the meter management unit 12 and the RRC control information acquired from the control unit 15 into the message. In addition, a terminal ID and a flag, which will be described later, are sometimes inserted into the message.

The transmission unit 14 performs error correction coding and modulation on the data that is a message obtained from the transmission data generation unit 13 to generate a transmission signal. Also, when data to be transmitted to the base station 20 is generated while the MTC device 10 is in an idle state, the transmission unit 14 generates a random access preamble as a transmission signal. The random access preamble is transmitted through the random access channel. Furthermore, the transmission unit 14 performs radio signal processing on the transmission signal, and up-converts the low-frequency baseband signal into a high-frequency radio signal. The transmission unit 14 transmits a transmission signal, which is a wireless signal, to the base station 20 via an antenna.

The control unit 15 controls the RRC connection between the MTC device 10 and the base station 20 and data transmission (uplink communication) from the MTC device 10 to the base station 20 . The control unit 15 has a terminal information management unit 16 , a flag setting unit 17 , and an RRC processing unit 18 .

The terminal information management unit 16 manages a terminal ID which is identification information preliminarily attached to the MTC device 10 . When inserting the terminal ID into the message, the terminal information management unit 16 outputs the terminal ID to the transmission data generation unit 13 .

When inserting the flag into the message, the flag setting unit 17 determines the value of the flag and outputs it to the transmission data generating unit 13 . The flag indicates whether MTC data sent to the MTC server 30 is included in the message before the RRC connection is established. For example, the flag setting unit 17 sets flag=1 when inserting MTC data into a message before RRC connection establishment, and sets flag=0 when not inserting MTC data.

The RRC processing unit 18 transmits and receives RRC control information to and from the base station 20, and performs processing of establishing an RRC connection and processing of releasing the RRC connection. For example, when the RRC connection is not established, the RRC processing unit 18 determines the timing at which the RRC connection request can be transmitted to the base station 20 based on the control information acquired from the receiving unit 11 . Then, the RRC control information, that is, the RRC connection request is output to the transmission data generation unit 13 . However, in the case of inserting MTC data into a message before establishing an RRC connection, an RRC connection request is not output.

FIG. 4 is a block diagram illustrating a base station. The base station 20 has a reception unit 21 , a received data processing unit 22 , a wired communication unit 23 , a transmission unit 24 , and a control unit 25 .

The receiving unit 21 performs radio signal processing on signals received from the MTC devices 10 and 10a via the antenna, and down-converts high-frequency radio signals into low-frequency baseband signals. Then, demodulation and error correction decoding are performed on the baseband signal, and the message transmitted by the MTC device 10 , 10 a is output to the reception data processing unit 22 . In addition, the receiving unit 21 detects the random access preamble transmitted by the MTC device 10, 10a.

The received data processing unit 22 extracts user data (including MTC data) and control information included in the message acquired from the receiving unit 21 under the control of the control unit 25 . The received data processing unit 22 outputs the extracted user data to the wired communication unit 23 , and outputs the extracted control information to the control unit 25 . The control information includes RRC control information.

Here, when acquiring a message transmitted by the MTC device 10 at a timing at which the RRC connection request can be transmitted, the received data processing unit 22 determines whether any of RRC control information and MTC data is inserted into the message. This determination is made by checking whether or not the terminal ID included in the message is registered in the terminal information storage unit 26 and whether or not the flag included in the message has a predetermined value. The details of the determination method will be described later.

The wired communication unit 23 is connected to the network 40 and is a communication interface for performing wired communication. The wired communication unit 23 transmits the MTC data acquired from the received data processing unit 22 and the control information for the MTC server 30 acquired from the control unit 25 to the MTC server 30 via the network 40 . Also, the wired communication unit 23 outputs the user data addressed to the MTC devices 10 and 10 a received from the MTC server 30 to the transmitting unit 24 .

The transmission unit 24 performs error correction coding and modulation on the user data obtained from the wired communication unit 23 and the control information obtained from the control unit 25 to generate a transmission signal. Also, when a random access preamble signal is detected by the receiving unit 21, the transmitting unit 24 generates a random access response as a transmission signal. Furthermore, the transmission unit 24 performs radio signal processing on the transmission signal to up-convert the low-frequency baseband signal into a high-frequency radio signal. The transmission unit 24 transmits a transmission signal, which is a wireless signal, to the MTC devices 10 and 10a via the antenna.

The control unit 25 controls access from the MTC devices 10 and 10a to the base station 20 and reception of MTC data from the MTC devices 10 and 10a. The control unit 25 has a terminal information storage unit 26 and an RRC processing unit 27 .

The terminal information storage unit 26 stores terminal IDs of wireless communication devices (including the MTC devices 10 and 10 a ) accessing the base station 20 that may transmit MTC data before establishing an RRC connection (including the MTC device 10 ). The terminal ID of the MTC device 10 may be pre-registered, or may be registered through signal transmission between the MTC device 10 and the base station 20 . In the latter case, the control unit 25 transmits control information indicating the terminal ID registered in the terminal information storage unit 26 to the MTC server 30 via the wired communication unit 23 .

The RRC processing unit 27 transmits and receives RRC control information with the MTC devices 10 and 10a, and performs processing of establishing an RRC connection and processing of releasing the RRC connection. For example, when an RRC connection request is acquired from the received data processing unit 22, the RRC processing unit 27 performs RRC protocol processing, and outputs RRC control information (RRC connection setting information) in response to the received RRC connection request to the transmission unit 24. .

Next, processing performed by the radio communication system according to the second embodiment will be described. First, the process of registering the terminal ID of the MTC device 10 in the base station 20 will be described, and then the process of the MTC device 10 transmitting MTC data to the MTC server 30 via the base station 20 will be described.

FIG. 5 is a sequence diagram showing the flow of terminal registration. The processing shown in FIG. 5 will be described following the step numbers.

(Step S11 ) The MTC device 10 sends the random access preamble to the base station 20 . The transmitted random access preamble is selected from a plurality of predefined signal sequence candidates. The message sent through step S11 is sometimes called message 1 (Msg1). Also, contention may occur in Msg1, that is, a plurality of wireless communication devices transmit the same signal sequence at the same timing.

(Step S12 ) When detecting Msg1 included in the received signal, the base station 20 transmits a random access response message to the cell of the own station. However, the base station 20 has not identified the source of Msg1 at this point. The message sent through step S12 is sometimes called message 2 (Msg2).

(Step S13 ) Upon receiving Msg2 from the base station 20 , the MTC device 10 transmits an RRC connection request message to the base station 20 . The RRC connection request message includes the identification information of the MTC device 10 . The message sent through step S13 is sometimes called Msg3.

(Step S14 ) Upon receiving Msg3 , the base station 20 identifies the MTC device 10 of the transmission source from the identification information included in Msg3 . Then, a process of establishing an RRC connection is performed, and an RRC connection setup message is sent to the MTC device 10 together with the received identification information. The message sent through step S14 is sometimes called message 4 (Msg4). Also, when a contention occurs in random access, the base station 20 transmits Msg4 to any one of the multiple transmission sources after the contention. If the Msg4 does not contain its own identification information, the MTC device 10 returns to step S11 and sends the Msg1 to the base station 20 again.

(Step S15 ) When receiving Msg4 from the base station 20 , the MTC device 10 performs processing for establishing an RRC connection, and returns an RRC connection setup complete message.

(Step S16 ) When establishing an RRC connection with the base station 20 , the MTC device 10 sends a terminal registration request message to the base station 20 . The terminal registration request message includes the terminal ID of the MTC device 10 .

(Step S17 ) When the base station 20 receives the terminal registration request message from the MTC device 10 , it registers the terminal ID of the MTC device 10 in its own station.

(Step S18 ) The base station 20 sends a terminal registration request message to the MTC server 30 via the network 40 . The terminal registration request message includes the terminal ID of the MTC device 10 .

(Step S19 ) When receiving the terminal registration request message from the base station 20 , the MTC server 30 registers the terminal ID of the MTC device 10 in its own device.

(Step S20 ) The MTC server 30 sends a terminal registration complete message to the base station 20 as a response to the terminal registration request message.

(Step S21 ) Upon receiving the terminal registration complete message from the MTC server 30 , the base station 20 sends the terminal registration complete message to the MTC device 10 .

(Step S22 ) When receiving the terminal registration completion message from the base station 20 , the MTC device 10 sends an RRC connection release message to the base station 20 to perform a process of releasing the RRC connection. Upon receiving the RRC connection release message from the MTC device 10, the base station 20 performs processing for releasing the RRC connection.

Therefore, by performing signal transmission between the MTC device 10 and the base station 20 , the terminal ID of the MTC device 10 can be registered in the base station 20 . In addition, the above signal transfer may only be performed when the MTC device 10 is initially connected to the base station 20 . In addition, from the viewpoint of security or the like, an expiration date may be set for the terminal ID registered in the base station 20, and signal transmission may be performed periodically.

FIG. 6 is a diagram showing the data structure of Msg3. The MTC device 10 having the function of transmitting MTC data without establishing an RRC connection transmits Msg3 of type A or type B shown in FIG. 6 . On the other hand, the MTC device 10 a that does not have the function of transmitting MTC data without establishing an RRC connection transmits Msg3 of Type C.

Msg3 of type A contains terminal ID, logo and MTC data. The flag of type A is set to a value indicating that MTC data is included (for example, flag=1). Msg3 of type B contains terminal ID, flag and RRC control information for establishment of RRC connection. The flag of type B is set to a value indicating that RRC control information is included (for example, flag=0). Msg3 of type C contains terminal ID and RRC control information.

Here, there is a possibility that the base station 20 also receives any one of types A, B, and C Msg3 in order to perform wireless communication with both the MTC devices 10, 10a. Therefore, the base station 20 first checks whether the terminal ID included in Msg3 is registered in the base station 20, and only if it is registered, checks the flag to determine the type of data included in Msg3.

FIG. 7 is a flowchart showing data transmission processing. The processing shown in FIG. 7 is executed by the MTC device 10 . The processing shown in FIG. 7 will be described following the step numbers.

(Step S31 ) The control unit 15 judges whether there is user data (including MTC data) to be transmitted to the base station 20 . In a case where there is user data to be transmitted, the process proceeds to step S32. In the case where there is no user data to be transmitted, the processing is ended.

(Step S32 ) The transmitting unit 14 transmits the random access preamble ( Msg1 ) to the base station 20 . The receiving unit 11 receives a random access response message ( Msg2 ) from the base station 20 . In addition, here, it is assumed that no competition of Msg1 occurs.

(Step S33 ) The control unit 15 determines the timing to transmit the Msg3 to the base station 20 by receiving the Msg2 from the base station 20 . Also, the control unit 15 judges whether or not the user data transmitted to the base station 20 is user data that can be transmitted without an RRC connection. For example, it is determined that MTC data of a predetermined size or less can be transmitted without an RRC connection, and other user data is determined not to be transmitted without an RRC connection. When transmission is possible without RRC connection, the process proceeds to step S34. In other cases, the process proceeds to step S35.

(Step S34 ) The transmission data generation unit 13 generates a message (Msg3 of type A described above) including the terminal ID, flag, and MTC data. The transmitting unit 14 transmits Msg3 to the base station 20 . The receiving unit 11 receives Msg4 as a response to Msg3 from the base station 20 . Thereby, the transmission process of the MTC data ends, and returns to the idle state.

(Step S35 ) The transmission data generation unit 13 generates a message (Msg3 of type B described above) including the terminal ID, flag, and RRC control information. The transmitting unit 14 transmits Msg3 to the base station 20 . The receiving unit 11 receives Msg4 which is an RRC connection setup message from the base station 20 .

(Step S36 ) The control unit 15 performs a process of establishing an RRC connection between the MTC device 10 and the base station 20 . The transmission data generation unit 13 generates an RRC connection setup complete message. The transmitting unit 14 transmits an RRC connection setup complete message to the base station 20 .

(Step S37 ) The transmission data generation unit 13 generates a message including user data. The transmitting unit 14 transmits the generated message to the base station 20 .

(Step S38 ) The transmission data generation unit 13 generates an RRC connection release message. The transmission unit 14 transmits the RRC connection release message to the base station 20 . The control unit 15 performs processing for releasing the RRC connection. Thus, return to the idle state.

Thus, the MTC device 10 can transmit MTC data to the base station 20 without an RRC connection. Also, by setting a flag in Msg3, the MTC device 10 can separately use data transmission performed without establishing an RRC connection and data transmission performed with an RRC connection established.

Here, the RRC protocol has a mobility management function, and contributes to improvement of communication quality when a wireless terminal device moves. On the other hand, it is assumed that the MTC device 10 connected to the meter does not move. In addition, it is assumed that the size of the MTC data transmitted by the MTC device 10 is small. Therefore, according to the second embodiment, it can be expected that the effect on communication quality achieved without establishing an RRC connection is small.

FIG. 8 is a flowchart showing data reception processing. The processing shown in FIG. 8 is executed by the base station 20 . The processing shown in FIG. 8 will be described following the step numbers.

(Step S41 ) The received data processing unit 22 judges whether or not Msg3 has been received from the MTC device 10 . When Msg3 is received, the process proceeds to step S42. When Msg3 is not received, the processing is ended.

(Step S42 ) The received data processing unit 22 determines whether or not the terminal ID included in Msg3 is registered in the terminal information storage unit 26 . When registered, the process proceeds to step S43. If not registered, the process proceeds to step S46.

(Step S43 ) The received data processing unit 22 judges whether or not the flag included in Msg3 has a predetermined value indicating that MTC data is included (for example, flag=1). When the flag is a predetermined value, the process proceeds to step S44. When the flag is not a predetermined value (for example, flag=0), the process proceeds to step S46.

(Step S44) The received data processing unit 22 extracts MTC data from the received Msg3. The wired communication unit 23 transmits the extracted MTC data to the MTC server 30 .

(Step S45 ) The control unit 25 generates a data reception response message as Msg4 . The transmitting unit 24 transmits Msg4 to the MTC device 10 . Thus, the receiving process of the MTC data ends.

(Step S46 ) The control unit 25 proceeds to the process of establishing an RRC connection, and generates an RRC connection setup message as Msg4 . The transmitting unit 24 transmits Msg4 to the MTC device 10 .

(Step S47 ) The receiving unit 21 receives a message including user data from the MTC device 10 . The received data processing unit 22 extracts user data from the message. Wired communication unit 23 outputs the extracted user data to network 40 .

(Step S48 ) The receiving unit 21 receives the RRC connection release message from the MTC device 10 . The received data processing unit 22 extracts RRC control information included in the RRC connection release message. The control unit 25 performs processing for releasing the RRC connection.

FIG. 9 is a sequence diagram showing the flow of data transmission without establishing an RRC connection. The processing shown in FIG. 9 will be described following the step numbers.

(Step S51 ) The MTC device 10 sends Msg1 to the base station 20 .

(Step S52 ) The base station 20 sends Msg2 to the MTC device 10 .

(Step S53 ) The MTC device 10 sends Msg3 (the aforementioned Msg of type A) containing MTC data to the base station 20 .

(Step S54 ) The base station 20 checks the terminal ID and flag included in the received Msg3 and determines that MTC data is included in Msg3 .

(Step S55 ) The base station 20 extracts the MTC data from the received Msg3 and transmits it to the MTC server 30 .

(Step S56 ) The base station 20 sends a data reception response message to the MTC device 10 as Msg4 . Therefore, no RRC connection is established between the MTC device 10 and the base station 20 , and data transmission from the MTC device 10 to the base station 20 ends.

FIG. 10 is a sequence diagram showing the flow of data transmission for establishing an RRC connection. The processing shown in FIG. 10 will be described following the step numbers.

(Step S61 ) The MTC device 10 sends Msg1 to the base station 20 .

(Step S62 ) The base station 20 sends Msg2 to the MTC device 10 .

(Step S63 ) The MTC device 10 sends the Msg3 containing the RRC control information (the aforementioned Msg3 of Type B) to the base station 20 .

(Step S64 ) The base station 20 confirms the terminal ID and the flag included in the received Msg3, and determines that the RRC control information is included in the Msg3.

(Step S65 ) The base station 20 enters the process of establishing an RRC connection, and sends an RRC connection setup message to the MTC device 10 as Msg4 .

(Step S66 ) The MTC device 10 performs a process of establishing an RRC connection, and sends an RRC connection setup complete message to the base station 20 .

(Step S67 ) The MTC device 10 sends user data to the base station 20 . The user data sent here may include MTC data.

(Step S68 ) If the received user data includes MTC data, the base station 20 transmits the MTC data to the MTC server 30 .

(Step S69 ) The MTC device 10 sends the RRC connection release message to the base station 20 . Thus, data transmission from the MTC device 10 to the base station 20 ends.

According to the wireless communication system of the second embodiment, it is possible to transmit MTC data from the MTC device 10 to the base station 20 without performing an RRC connection establishment process. Therefore, even when the MTC device 10 intermittently transmits small-sized MTC data, it is possible to efficiently transmit the MTC data while reducing the overhead of wireless communication accompanying establishment/disconnection of the RRC connection. In addition, in the radio communication system according to the second embodiment, in order to authenticate the terminal ID, the base station 20 may mix MTC devices that can transmit data without establishing an RRC connection and MTC devices that cannot transmit data. .

In addition, in the above description of the second embodiment, Msg3 was used as a message for inserting MTC data. However, the message that can be used to transmit the MTC data is not limited to Msg3, and other messages at the timing at which the MTC device 10 can transmit RRC control information to the base station 20 may be used.

With regard to the foregoing description, the principles of the invention are merely illustrated. In addition, for those skilled in the art, various modifications and changes can also be implemented. The present invention is not limited to the precise structures and application examples shown and described above. It should be understood that all corresponding modifications and equivalents are It is within the scope of the invention to be determined by the appended claims and their equivalents.

Symbol Description

1, 2: wireless communication device; 1a: control unit; 1b: sending unit; 2a: receiving unit; 2b: data processing unit.

Claims (7)

1. A wireless communication method of a wireless communication system, the wireless communication system comprising a first wireless communication device and a second wireless communication device, the first wireless communication device transmits data to the second wireless communication device, the wireless communication The method is characterized by, When the connection with the second wireless communication device is not established, the first wireless communication device transmits to the second wireless communication device a transmission including the wireless communication device indicating the transmission source at the timing when the control information can be transmitted. a message of source information, wherein the control information is used for the processing of connection establishment, the second wireless communication device receives, from the first wireless communication device, the message transmitted at a timing when the first wireless communication device can transmit the control information, In a case where the wireless communication device of the source indicated by the source information included in the received message is registered in the second wireless communication device, the second wireless communication device obtains the extract data different from the control information, When the wireless communication device of the source indicated by the source information included in the received message is not registered in the second wireless communication device, the second wireless communication device and the second wireless communication device 1 The wireless communication device establishes a connection. 2. The wireless communication method according to claim 1, wherein: When data different from the control information is extracted from the received message, the second wireless communication device does not perform the connection establishment process. 3. The wireless communication method according to claim 1, wherein: The first communication device inserts data different from the control information into the message instead of the control information. 4. The wireless communication method according to claim 1, wherein: The message includes flag information indicating whether there is data different from the control information, The second wireless communication device extracts data different from the control information when it is determined from the flag information that the message includes data different from the control information. 5. The wireless communication method according to claim 1, wherein: The message is a message sent after the first wireless communication device performs random access to the second wireless communication device and before establishing a connection. 6. A wireless communication device that receives data from other wireless communication devices, the wireless communication device being characterized by having: a receiving unit that receives, from the other wireless communication device that has not established a connection with its own device, a message including transmission source information indicating a wireless communication device that is a transmission source, that is transmitted at a timing when the other wireless communication device can transmit control information; message, wherein the control information is used for the process of establishing a connection; and The data processing unit is configured to obtain the data processing unit from the extracting data different from the control information from the message, and processing the data when the wireless communication device of the transmission source indicated by the transmission source information contained in the received message is not registered in the own device. The department establishes a connection with the other wireless communication device. 7. A wireless communication system comprising a first wireless communication device and a second wireless communication device, wherein the first wireless communication device transmits data to the second wireless communication device, wherein the wireless communication system is characterized in that The first wireless communication device includes a control unit that determines a timing at which control information can be transmitted to the second wireless communication device when the connection with the second wireless communication device is not established, wherein the control information a process for establishing a connection; and a transmission unit that transmits a message including transmission source information indicating a transmission source wireless communication device to the second wireless communication device at a timing determined by the control unit, The second wireless communication device includes: a receiving unit configured to receive the message from the first wireless communication device at a timing when the first wireless communication device can transmit the control information; and a data processing unit configured to When the second wireless communication device is registered with the wireless communication device of the transmission source indicated by the transmission source information included in the message received by the receiving unit, the data processing unit obtains the data different from the control information is extracted from the message, and when the wireless communication device of the transmission source indicated by the transmission source information included in the received message is not registered in the second wireless communication device , the data processing unit establishes a connection with the first wireless communication device.